System and method for controlling a connection of a meter to a power line

ABSTRACT

The disclosure relates to a meter for monitoring usage of power provided by a power transmission system to a site. The meter comprises: a communication module to generate communications carried over the transmission system; a relay having a first position connecting power from the transmission system to the site and a second position disconnecting power; a request manager module to process messages from a head end associated with the transmission system; a meter module connected to a power feed associated with the transmission system to provide readings relating to the power used at the site; an event manager module to evaluate new events queued in a message queue received by the meter and after evaluating the new events to send a message to the head end relating to the earliest event in the message queue; a connection manager module managing the power connection to the transmission system.

RELATED FILINGS

This application is a continuation application of U.S. patentapplication Ser. No. 13/302,756 filed Nov. 22, 2011.

FIELD OF DISCLOSURE

The disclosure described herein relates to a system and method forcontrolling a connection, such as a power connection, of a meter, suchas a utility meter, to a power line.

BACKGROUND

Powerline networks provide energy from a power source (e.g. ahydroelectric dam) to a network of residential and commercial customersites. The power carried over transmission lines in the network can bedistributed through a series of sub-networks to the actual sites. Metersat the sites monitor the power usage, which provides usage data forbilling purposes. Some meters provide automated remote transmissions ofreading data to a central location, such as a head end of the powernetwork. Such meters have limited capabilities.

SUMMARY OF DISCLOSURE

In a first aspect, a meter for monitoring usage of power provided by apower transmission system to a site is provided. The meter comprises: acommunication module to generate communications carried over the powertransmission system; a relay having a first position where power fromthe power transmission system is connected to the site and a secondposition where the power is disconnected from the site; a requestmanager module to process messages received through the communicationmodule from a head end associated with the power transmission system; ameter module connected to a power feed associated with the powertransmission system to provide readings relating to the power used atthe site; an event manager module to evaluate new events queued in amessage queue received by the meter and after evaluating the new eventsto generate and send a message to the head end relating to the earliestevent in the message queue; and a connection manager module to evaluatethe readings and data relating to past power usage at the site andgenerate connection signals for the relay for the meter to the powertransmission system, to evaluate the readings and control the schedulemanager in generating the control signal, and to generate a signal forthe relay to disconnect the power when a condition in the powertransmission system has been detected by or reported to the meter.

In the meter, the event manager module may further: send a secondmessage relating to the earliest event to the head end when a responsemessage is not received from the head end to the message within atimeout period; and send a third message relating to a next earliestevent in the message queue to the head end when the response message isreceived from the head end.

The meter may further comprise a schedule manager module to generate acontrol signal to provide a fraction of the power to the site.

In the meter, the condition may be an over-voltage condition over athreshold over a period of time.

In the meter the threshold of voltage value may be provided to the meterfrom a message received through the power transmission system.

In the meter, the connection manager module may generate a second signalfor the relay to connect the power to the site when a reset conditionhas been detected by the meter module.

In the meter, the connection manager module may also generate a secondsignal for the relay to connect the power to the site when a disconnectcondition has been detected by the meter module.

In the meter, the request manager module may process a broadcast messagereceived from the head end of the power transmission system relating toa cluster command for meters in a subnet that include the meter.

In the meter, the condition may be detection at least one of opening acase of the meter and disconnection of the meter from the power.

In the meter, the connection manager module may further generate thesignal for the relay after receiving a disconnect signal from the headend of the power transmission system.

In the meter, the schedule manager module may further obtain a pluralityof readings from the meter module and provides results of the pluralityof readings to the connection manager module.

In the meter, the plurality of readings may be made according to aschedule provided by the schedule manager module.

In the meter, the schedule manager module may further update a usagerate for readings made by the meter module.

In the meter, the schedule manager module may further synchronize aclock of the meter with a system time managed at the head end of thepower transmission system.

In a second aspect, a method for monitoring usage of power provided by apower transmission system to a site through a meter is provided. Themethod comprises: obtaining and storing readings for a power feedassociated with the site; evaluating the readings and data relating topast power usage at the site; generating connection signals for themeter to the power transmission system in view of the readings;evaluating new events queued in a message queue received by the meter;after evaluating the new events, generating and sending a message to thehead end relating to the earliest event in the message queue; andcontrolling a relay having a first position where the power is connectedto the site and a second position where the power is disconnected fromthe site when an over-voltage condition on the power transmission systemhas been detected by or reported to the meter.

The method may further comprise: sending a second message relating tothe earliest event to the head end when a response message is notreceived from the head end to the message within a timeout period; andsending a third message relating to a next earliest event in the messagequeue to the head end when the response message is received from thehead end.

The method may further comprise evaluating the readings and controllinga schedule manager to generate a control signal to provide a fraction ofthe power to the site.

The method may further comprise generating a connection signal toconnect the power to the site when a reset condition has been detected.

In the method, the relay may also be set to the second position when atleast one of opening a case of the meter and disconnection of the meterfrom the power is detected.

In another aspect, a meter for monitoring usage of power provided by apower transmission system to a site is provided. The meter comprises: acommunication module to generate communications carried over the powertransmission system; a request manager module to process messagesreceived through the communication module from a head end associatedwith the power transmission system; a meter module connected to a powerfeed associated with the power transmission system to provide readingsrelating to the power used at the site; a connection manager module toevaluate the readings and data relating to past power usage at the siteand to generate connection signals for the meter to the powertransmission system in view of the readings; and a relay having a firstposition where the power is connected to the site and a second positionwhere the power is disconnected from the site, the relay beingcontrolled by the connection signals. For the meter, the connectionmanager module generates a first signal for the relay to disconnect thepower when an over-voltage condition or an over-current condition on thepower transmission system has been detected by or reported to the meter.

In the meter, the over-voltage condition may include a threshold ofvoltage value over a period of time.

In the meter, the threshold of voltage value may be provided to themeter from a message received through the transmission system.

In the meter, the connection manager module may generate a second signalfor the relay to connect the power to the site when a reset conditionhas been detected by the meter module.

In the meter, the connection manager module may also generate the firstsignal for the relay to connect the power to the site when a disconnectcondition has been detected by the meter module.

In the meter, the relay may further have a third position between thefirst and the second positions, where for the third position a fractionof available power for the site is provided to the site.

The meter may further comprise an event manager module to evaluate newevents queued in a message queue received by the meter.

The meter may further comprise a schedule manager module to scheduleobtaining a plurality of readings from the meter module and to provideresults of the plurality of readings to the connection manager module.

In the meter, the plurality of readings may be made according to aschedule provided by the schedule manager module.

In the meter, the schedule manager module may update a usage rate forreadings made by the meter module a schedule.

In the meter, the request manager module may process a broadcast messagereceived from the head end relating to a cluster command for meters in asubnet that include the meter.

In the meter, the schedule manager module may synchronize a clock of themeter with a system time managed at the head end.

In a further aspect, a method for monitoring usage of power provided bya power transmission system to a site through a meter is provided. Themethod comprises: obtaining and storing readings for a power feedassociated with the site; evaluating the readings and data relating topast power usage at the site; generating connection signals for themeter to the power transmission system in view of the readings;controlling a relay having a first position where the power is connectedto the site and a second position where the power is disconnected fromthe site by the connection signals. In the method, a first connectionsignal of the connection signals is to disconnect the power when anover-voltage condition or an over-current condition on the powertransmission system has been detected by or reported to the meter.

In the method, a second connection signal of the connection signals maybe to connect the power to the site is generated when a reset conditionhas been detected.

In still another aspect, a data transmission system for communicatingwith meters at remote locations through power transmission lines isprovided. The system comprises: a first power network providing power afirst voltage level; a server connected to the first network, the servercommunicating with a plurality of meters in communication with the firstnetwork; a second power network connected to the first network anddistributing power at a second voltage level to the remote locations,the second voltage level being lower than the first voltage level; and agateway connecting the first network to the second network, the gatewayrelaying messages from the first network to a subset of meters in thesecond network and relaying response messages to the broadcast messagefrom the subset of meters to the server. In the system, the downstreamand upstream data communications are encoded in internet protocol (IP)signals in the power transmission network.

In another aspect, a method for communicating from a central locationthrough power transmission lines in a power network with a plurality ofmeters is provided. The power network comprises a first power networkproviding power a first voltage level and a second power networkconnected to the first network. The second network distributes power ata second voltage level to a remote location, where the second voltagelevel being lower than the first voltage level. The method comprises:from a server associated with the central location, obtaining statusupdates from the meters by transmitting broadcast messages to the firstnetwork destined for delivery to a first set of the meters, where a setof broadcast messages is transmitted in a block of messages, with aportion of the set of broadcast messages sent to meters in the secondnetwork; monitoring for responses to the portion of the set of broadcastmessages from the meters in the second network; and transmitting asecond set of the broadcast messages to the first network destined fordelivery to a second set of meters, when the responses to the portion ofthe set of broadcast messages at least matches a size of the second set.In the method, the first set of meters is less in number than a currentload index for a server processing the responses.

In still another aspect, a meter for monitoring usage of power providedby a power transmission system to a site is provided. The metercomprises: a meter module connected to a power feed associated with thepower transmission system to provide readings relating to the power; amessaging module to provide messages to the power transmission system; aconnection to an alternating current (AC) power supply; a rectifiercircuit connected to the AC power supply to generate a direct current(DC) power signal; a capacitive circuit connected to an output of therectifier circuit, the capacitive circuit including a capacitor forstoring a voltage for temporarily providing replacement power for therectifier circuit; and a switching regulator circuit connected to theoutput of the rectifier circuit and the capacitive circuit, theswitching regulator converting the DC voltage signal to a stepped downvoltage signal for the meter module.

In a further aspect, a method for monitoring usage of power provided bya power transmission system to a site at a meter is provided. The methodcomprises: charging a capacitive circuit located between a rectifiercircuit connected to an AC power supply for the meter that generates aDC power signal for the meter and a switching regulator circuitconnected to the output of the rectifier circuit, the switchingregulator converting the DC voltage signal to a stepped down voltagesignal for the meter module; and when the AC power supply fails,discharging the capacitive circuit to provide a voltage to the switchingregulator.

The method may further comprise generating and sending a message to thepower transmission system from the meter alerting of failure of the ACpower supply.

The method may further comprise: maintaining an internal clock in themeter for synchronization with a clock maintained by a head end; andadjusting the internal clock with the clock maintained by the head endwhen a discrepancy between the internal clock and the clock maintainedby the head end is detected.

The method may further comprise: detecting a low voltage condition wherean output from the capacitive circuit drops below an operationalthreshold for the meter; and generating and sending a power loss messageupon detection of the low voltage condition to the power transmissionsystem. In the method, the power loss message may be carried on amessage carrier having a carrier frequency between approximately 2 MHzand 30 MHz to bridge a discontinuity in the power transmission system.

In another aspect, a system for communicating with a meter at a remotelocation through power transmission lines is provided. The systemcomprises: a head end for collecting and analyzing data from the meter;a power transmission network connected to the meter and to the head end;and a gateway connected to the power transmission network. The powertransmission network provides both power to the remote location and datacommunications to the networks; the power transmission network includesa first network providing a first voltage and a second network connectedto the first network and the remote location, the second networkproviding a second voltage lower than the first voltage to the remotelocation. The gateway is located at a bridge between first and secondnetworks. The gateway provides an interface communication point for thedata communications between the first and second networks; the gatewayforwards the data communications between the first and second networkswith no effective content-based delay of transmission of the datacommunications. In the network, the data communications are carried overthe power transmission network following Internet protocol (IP)communication standards and the gateway adheres to the IP communicationstandards. The system provides high speed communications as messages aretransmitted between the head end and the meter in real time.

In the system, the meter may provide an interface at the remote locationfor an IP connection to the internet through the power transmissionnetwork.

In the system, the meter may obtain power signal measurements relatingto signals received from the power transmission network; the meter maysend a message containing data relating to the power signal measurementsto the head end; the head end may analyze the power signal measurementsto the head end to identify a signal to noise ratio (SNR) for thesignals received at the meter; and the head end may analyze the SNR toidentify operating characteristics of the power transmission network.

The head end may analyze the power signal measurements to the head endto identify a carrier frequency response (CFR) value for the signalsreceived at the meter. The head end may analyze the CFR value toidentify operating characteristics of the power transmission network.

In the system, the meter may provide real time data readings from adevice at the remote location to the head end.

In the system, the meter may be selectively connected and disconnectedfrom the power transmission network.

In the system, the meter may be disconnected from the power transmissionnetwork when any one of the following conditions is detected: an overvoltage condition of the power transmission network; an over currentcondition of the power transmission network; or tampering of the meter.

In the system, meter may comprise a power reserve capacitive circuit toprovide residual power to the meter when power from the powertransmission network has been interrupted.

In the system, the meter may have an internal clock which isperiodically synchronized with a clock maintained by the head end.

In another aspect, a method embodying the features provided above isprovided.

In other aspects, various combinations and sub-combinations of the aboveaspects are provided.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure will now be described, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1A is an overview of a network implementing an embodiment of thedisclosure including a head end communicating with a plurality of metersat end units and a gateway connected between the end units and the headend;

FIG. 1B is an overview of data communication elements of the network ofFIG. 1A;

FIG. 1C is a block diagram of the bridging device of FIG. 1B;

FIG. 2A is a schematic diagram of the head end as provided in FIG. 1A;

FIG. 2B is a block diagram of functions of the head end of FIG. 2A;

FIG. 3A is a schematic diagram of features of a meter at an end unit inthe network of FIG. 1A;

FIG. 3B is a schematic diagram of a power reserve module of the meter ofFIG. 3A;

FIG. 4 is a flow chart showing a connection algorithm used by the meterof FIG. 3A;

FIG. 5 is a state diagram of a state machine implementing a disconnectfunction for the meter of FIG. 3A;

FIG. 6 is a flow chart of an algorithm for reading data by the meter ofFIG. 3A;

FIG. 7 is a state diagram of the algorithm for meter reading of FIG. 6;

FIG. 8 is a time line diagram of events occurring at the head end and ameter during an exemplary meter reading configuration in the network ofFIG. 1A;

FIG. 9 is another time line diagram of events occurring at the head endand a meter during an exemplary meter reading process in the network ofFIG. 1A;

FIG. 10 is another time line diagram of events occurring at the head endand a meter during an exemplary tampering detection process of the meterin the network of FIG. 1A;

FIG. 11 is a flow chart showing a synchronization algorithm used by themeter of FIG. 3A;

FIG. 12 is a flow chart showing a clock synchronization algorithm usedin the meter of FIG. 3A;

FIG. 13 is a flow chart showing a signal measurement algorithm used todetect condition in the network of FIG. 3A;

FIG. 14 is a snapshot of a data collection configuration graphical userinterface (GUI) generated on a display of a client associated with thehead end of FIG. 3A;

FIG. 15 is a snapshot of a communications link GUI generated on adisplay of a client associated with the head end of FIG. 3A;

FIG. 16 is a snapshot of a performance GUI generated on a display of aclient associated with the head end of FIG. 3A; and

FIG. 17 is a flow chart showing a data collection/analysis algorithmexecuted at a client associated with the head end of FIG. 3A.

DETAILED DESCRIPTION OF AN EMBODIMENT

The description which follows and the embodiments described therein areprovided by way of illustration of an example or examples of particularembodiments of the principles of the present disclosure. These examplesare provided for the purposes of explanation and not limitation of thoseprinciples and of the disclosure. In the description which follows, likeparts are marked throughout the specification and the drawings with thesame respective reference numerals.

Exemplary details of embodiments of the present invention are providedherein.

FIG. 1A illustrates one embodiment of a high speed advanced meteringinfrastructure (“AMI”) system 100. System 100 provides both electricitytransmission and data transmission from power grid 102 to units 104.Units 104 are a physical location requiring power, such as a house, anapartment building, an office tower, a shopping mall, a factory, etc.Network operations center 106 is connected to system 100 and providesadministrative and network management functions for system 100.

From an electrical transmission point of view, power distribution systemincludes medium voltage (“MV”) network 108 and low voltage (“LV”)network 110. Power cables of medium voltage network 108 are MV lines andpower cables of LV network 110 are the LV lines. Voltages carried by MVnetwork 108 range from about 600 volts (V) to about 50 kV and voltagescarried by LV network 100 range from about 100 V to about 600 V.Distribution transformers 112 are located at nodes between MV networksand a set of end units 104. Transformers 112 convert voltages from MVnetwork 108 from MV values to LV values. Distribution transformers 112have a primary side connected to a first voltage (e.g., MV network 108)and a secondary side for providing an output voltage. In one embodiment,the secondary output provides a lower voltage (e.g., LV network 110).Distribution transformers 112 provide voltage conversion for powerdistribution system to units 104. Thus, power is carried from substation114 to distribution transformer 112 over one or more MV power lines.Power is carried from distribution transformer 112 to its units 104 viaone or more LV power lines. Units 104 are located at any premisesrequiring electricity, including, without limitation, residential homes,businesses, and industrial complexes. Power is provided at householdvoltage and current rates. In North American power is provided at 120volts (V). At each end unit 104, meter 116 is provided, which monitorspower usage in network 100 by an end unit 104.

In addition, distribution transformer 112 may function to distributeone, two, three, or multi-phase voltages to units 104, depending uponthe demands of the users. Distribution transformer 112 may be a pole-toptransformer located on a utility pole, a pad-mounted transformer locatedon the ground, or a transformer located under ground level.

This embodiment of system 100 also provides data communications overpowerlines (such as through networks 108 and 110) through broadband overpowerline (“BPL”) technology through network 134. For system 100,transmission of data is provided over networks 108 and 110 between headend 118 and meters 116. Additional data communications elements includebackbone network 120, router 122, fiber optic/radio frequency (“RE”)network 124 and BPL gateways 126. Head end 118 is located at a utilitynetwork operations center (“NOC”), and router 122 is located insubstation 114. BPL gateways 126 are located at distributiontransformers 112. In this embodiment, data transmission network betweensubstation 114 and distribution transformers 112 is through MV network108 or fiber optical/RF network 124. Various transmission/datacommunication technologies may be used to carry data for backbonenetwork 120, including, without limitation, fiber optics, cable, plainold telephone system (POTS), and other technology known to personskilled in the art. MV network 108 provides one data network backbone tosupport AMI system 100 through LV network 110. In the portion of system100 that is formed in LV network 110, network 110 has an uplink portconnecting to transformer 112; this uplink port in one embodiment is anEthernet port running TCP/IP protocol. This port can be connected withvarious types of backhaul connections, including connections to MVnetwork 108, fiber optical network 124, a wireless communicationnetwork, a GPRS network, etc. As shown in FIG. 1A, MV network 108provides one backhaul network implementation. If a networkimplementation utilizes a different backhaul network, such as fibernetwork 124 instead network 108, then the implementation may dispensewith having MV powerline network 108 as a backhaul for network 110.System 100 provides data throughput rates in the order of approximately40 Mbps on the physical layer for the network.

FIG. 1B provides additional detail on communication network 134 of FIG.1A.

Head end 118 further comprises a server and a head end client 204 (FIG.2). Head end 118 collects data from meters 116 at units 104, analyzesdata and other network operating conditions (both for networks 108 and110) and provides commands and instructions to meters 116, based on theanalysis or predetermined scripts. Meters 116 collect telemetric datafrom their respective units 104 (such as power usage data, broadbandcommunication network data, device status information, etc.) and providethe data to head end 118, through network 134. Each meter 116 comprisesa communication module 128 and a meter module 130. Communication module128 provides data communications, data analysis and other features forenabling communications between meter 116 and head end 118. Meter module130 analyzes source data detected from sensors connected to meter 116.Such sensors include an electricity usage monitoring meter and any otherdevice providing trackable data on events occurring at unit 104.Communication module 128 receives and processes data from meter module130 and provides related communication data to head end 118. Forexample, in one configuration, when communication module 128 hasdetected a meter event at meter module 130 and needs to report to headend 118, communication module 128 first constructs an IP packet messagewith head end 118 as the destination.

Through network 134, instead of head end 118 communicating directly witheach meter 116, BPL gateways 126 are provided to manage communicationsbetween head end 118 and a set of meters 116. As such, network 134 isorganized in a tree configuration with head end 118 at the root,gateways 126 at a first level underneath the root. Router 122 acts anetwork connecting device for network 134 and/or MV network 108 andinterchanges data packets between them. The data packets contain addressinformation used by router 122 to determine if the source anddestination are on the same network, or if the data packet must betransferred from one network to another. In one embodiment, gateway 126is located at LV electricity transformer 114. BPL gateway 126 andrelated meters 116 belonging to the same LV cell form a communicationnetwork 134 in a tree topology. BPL gateway 126 is the root of the tree.The BPL gateway 126 manages the LV network 110 in a medium accesscontrol (“MAC”) layer based on time division multiple access/timedivision duplex and parent-child concept. In one embodiment, each LVcell may comprise of up to 300 meters 116. Gateway 126 also providesinterface between backbone network 120 and meters 116 in a given LVcell/network.

Data carried in MV network 108 and fiber network 124 for system 100 maybe essentially the same content. In one configuration, system 100 mayutilize a fiber network (including part of network 124) from head end118 to substation 114 and utilize MV network 108 to connect to gateway126. Alternatively system 100 may utilize a fiber network from head end118 to gateway 126. It will be seen that utilizing network 108 as partof system 100 has an advantage of reusing a transmission infrastructureof the MV power lines without rebuilding a separate network.

In network 134, meters 116 are a second level connected to theirrespective gateway 126. Other configurations and subroots can beprovided.

Gateways 126 serve as a transparent network communication interfacebetween meters 116 and head end 118. Communications between meters 116and gateway 126 are provided through the LV lines in network 110, shownas high speed BPL channel 132. Communications between gateway 126 andhead end 118 can be provided over MV network 108 and/or network 124.When gateway 126 processes a transmission from meter 116 intended forhead end 118, it forwards the transmission to router 122 withoutexamining its payload contents. Similarly, when gateway 126 processes atransmission from head end 118 for meter 116 it does not impede the flowof the message downstream.

BPL gateway 126 provides minimal impedance to the flow of data betweenhead end 118 and meters 116. As such, real time data and instructionscan be provided between head end 118 and meters 116. For example, inprocessing a communication from meter 116 to gateway 126, upon receiptof the related data packet, in one embodiment gateway 126 does notexamine the payload of the packet and does not hold the transmission ofthe packet. The packet may be examined to identify destinationparameters. Preferably any queuing of the packet is restricted totransmission issues for the network. The contents of the payload or thesource meter 116 information is not used as a criteria for determiningwhether and/or when to forward the packet. In one embodiment, BPLgateway 126 is a communication device that is part of the networkcommunication infrastructure and is not built with any meteringintelligence. Gateway 126 effectively provides no content-based delay oftransmission of the packet. Such BPL gateway 126 is thus completelytransparent to automatic meter reading (“AMR”) transactions in system100.

In one network configuration, gateway 126 operates as a bridging devicefor network 110 (and ultimately network 108) with meter 116 to translatecommunications from one protocol in one network to the bridged network.Here, gateway 126 translates communications between network 110 encodedin a powerline media protocol to an Ethernet media protocol for meter116. In system 100, when initiating communications from head end 118 tometer 116, head end 118 creates an IP packet with a destination IPaddress of meter 116. This packet is inserted into network 108 at headend 118 and is routed via the related TCP/IP protocol gateway 126,passing through intermediary network devices including backbone network120, routers 122 and gateway 126 before reaching meter 116. Inprocessing communications, for example, router 122 examines thedestination of the data packet and forwards the data packet to backbonenetwork 120. To reach head end 118, the data packet may need to passthrough one or more routers 122.

An embodiment also provides communications backup. When communicationchannel quality issues between a particular meter 116 and gateway 126are detected, that meter 116 may transmit its data packet to anothermeter 116(b) in the local network 134. In turn, meter 116(b) forwardsthe data packet to gateway 126. As such, in this embodiment, secondmeter 116(b) may be used as a message repeater for meter 116.

Error detection and message repeating is managed in part by gateway 126for its connected devices (including meters 116). Gateway 126 has accessto a routing table for its meters 116 and other network connections.Periodically, gateway 126 inspects its listed connections (using itsrouting table) for connected carriers. Gateway 126 may receive statusmessages from meters 116 and other connected devices. By analyzing thesemessages, gateway 126 can determine the connectivity status of meters116. As such, if an error connection condition is identified from aparticular meter 116, gateway 126 can initiate commands to neighbouringdevices (including meter 116 b) to provide an alternative communicationpath for meter 116 to gateway 126.

Using BPL technology, configuration system 100 provides high speedtwo-way communications between head end 118 and meters 116. Effectively,head end 118 can be provided with telemetric data from meters 116 inreal time. System 100 reduces messaging delays and unnecessary queuingof communications (both downstream from head end 118 to meters 116 andupstream from meters 116 to head end 118).

BPL technology as implemented in system 100 provides networkconnectivity layers up to the TCP/IP layer. Gateway 126 and meters 116are packet based and are IP-addressable. System 100 also uses a packetswitching network that allows multiple concurrent transactions to beinitiated from head end 118 over the TCP/IP network to reach many meters116 directly. Devices in system 100 are preferably always connected tosystem 100. For example, when a message from a device in system 100 iscreated and inserted to system 100 for transmission, the devicepreferably does not have to go through a log-on process. Similarly, adevice receiving a message preferably does not have to go through alog-on process before checking for messages. This physical levelprovides data integrity, which can eliminate or reduce the need forhandshaking between devices. This implementation provides improvedperformance in terms of speed and message redundancy over existingcommunication protocols of existing AMI systems, where data istransmitted serially and devices must log on to access functions.

An embodiment of system 100 uses simple network management protocol(SNMP) for communications between head end 118 and meters 116. Otherapplication larger network protocols may also be used for this purpose.Communication module 128 has modules to decode SNMP message and requesta specific OBIS object from the meter module 130. Network efficiency insystem 100 is improved by providing data analysis intelligence incommunication module 128 inside meter 116 as AMI data processing may beoperated in parallel.

Use of BPL in system 100 provides electrical transmission and datacollection and transmission in one system. This allows large scale andhigh speed data collection by head end 118 and stable communication forsystem 100.

FIG. 1B shows further details of a meter 116 at unit 104. At unit 104, aseries of smart devices 136 are provided that connect to meter 116.Therein, where data communication between head end 118 and smart devices136 are provided through meter 116. Smart devices 136 may includerefrigerators, washers, dryers, plug-in electric car chargers, and anyother electronic devices or appliances and provide operating telemetricsto electricity their usage, status and other features.

In one embodiment, meter 116 may repeat communications for other smartdevices 136 coupled to LV network 110 and also provide communications toone or more of smart devices 136 operated on other types of networkingprotocols, such as a Zigbee (trade-mark) network, through bridgingdevice 138. In this embodiment, meter 116 further functions as a bypassdevice and repeater simultaneously, providing additional flexibility andredundancy for messaging among elements in system 100.

In an embodiment, meter 116 will receive upstream transmission packetsfrom one or more smart devices 136, through bridging device 138 or byitself. Meter 116 will retransmit those transmissions on BPL channel 132to gateway 126, which in turn will retransmit the packets to router 122and ultimately to head end 118. Smart device 136, bridging device 138and meter 116 contain information stored in their memory modules toreceive packets address to it and to re-address those packets with theaddress of the corresponding destination device.

FIG. 1C shows a block diagram of one embodiment of bridging device 138.Bridging device 138 include a powerline port (not shown) which convertspowerline data into serial data. This serial data can be furtherconverted to another protocol used by smart devices 136. Depending onthe type of smart network at the premises, for instance, a radiofrequency (RF) based network, the converted signal may be provided intoa RF transceiver for communication with other smart devices 136 in unit104.

The extension of data transmission and processing capabilities of system100 to unit 104 can be used to provide other IP data services such asbroadband internet, voice over IP, and video surveillance, through BPLmodem 140. Modem 140 receives a powerline signal and converts it to anEthernet signal which provides network connectivity, including, withoutlimitation, access to the Internet, to computer related equipment. Assuch, meter 116 provides a single interface for monitoring power usageat unit 104 and additional network connectivity for unit 104. Previousprior art systems do not provide both these features.

Now, further detail is provided on head end 118 at 200. FIG. 2A showshead end 118 and AMI head end system client 204. Communications betweenhead end 118 and client 204 may be through provided through network 202.Client 204 provides a control interface for an administrator for headend 118. Software for head end 118 is installed on one or multipleserver computers having a microprocessor and communication connection tothe network, which are typically located at the Network OperationsCentre (NOC). Software for the head end client 204 is installed on aconnected computer. Software for head end 118 and head end client 204may be deployed on the same computer or on one or more differentcomputers. Communication network 202 may be a private or public network.Head end client 204 generates graphical user interfaces allowingadministrators and operators of head end 118 to access services providedby head end 118 and to monitor, configure, and control various aspectsof system 100, including, without limitation, gateways 126, meters 116and communication connectivity quality of MV network 108 and LV network110.

In one embodiment, head end 118 comprises query manager (“NQM”) 206,configuration manager 208, event manager 210, and information requestmanager 212. Head end 118 further comprises Dynamic Host ConfigurationProtocol (“DHCP”) server 214, network time protocol (“NTP”) server 216,Trivial File Transfer Protocol (“TFTP”) server 218, and database server220, each of which provides functional modules of head end 118 toprovide network management capability in system 100. Event manager 210provides fault detection and notification capabilities, which includegeneration of alerts, automated actions, event correlation,trap/event/alert filtering to detect, isolate, and notify malfunctionsin system 100. Information request manager 212 allows head end systemclient 204 to request metering data and network management informationstored in database server 220. NTP server 216 provides clocksynchronization capability for meters 116. TFTP server 218 allows BPLgateway devices 126 and meters 116 to download new firmware remotely.NQM 206 is responsible for pulling and receiving event data or scheduleddata collections from BPL network elements, such as meters 116 and/orgateways 126. Configuration module 208 initializes each BPL networkelement and manages their configurations. Event manager 210 processesevents (e.g. messages, alarms, etc.) received by NQM 206, and stores andcorrelates event data into information and responses used by head end118. Request manager 212 communicates with client software 206 and relaymessages between client 206 and head end 118. Servers 214, 216, 218 and220 support computer services provided on a Microsoft Windows(trade-mark) operating system platform. Comparable servers are providedin other operating system platforms, such as in linux (trade-mark) orUNIX (trade-mark).

NQM 206 also is a data collection engine, collecting system-widemetering data from meters 116 located at units 104. It also collectsnetwork management information from BPL gateways 126 and meters 116. NQM206 determines status information for elements in system 100, such aswhether a BPL gateway 126 or a meter 116 is active or not, whether ithas exceeded key performance parameters, and identifies inter-devicelink faults. Data collection may be performed at regular scheduledintervals or on demand.

Configuration manager 208 discovers and registers newly installed BPLgateways 126 and meters 116. New meters may initially need torequest/obtain an IP address. This request may be intercepted by manager208 and its MAC address information may be evaluated and compare if thisMAC address exists in database 220 at head end 118 to determine if themeter is trying to register for service. Configuration manager 208 alsoprovides remote control and configuration capability to allowadministrators and operators having access to head end client 204 tocontrol and configure gateways 126 and meters 116 remotely. In oneembodiment, when an operator issues a disconnect command for a meter 116through head end client 204, configuration manager 208 will send thecommand to a specified meter 116 to disconnect the electrical service ofa corresponding end unit 104 from LV network 110. Configuration manager208 also allows an operator to send a new time of use (“TOU”) table tometer 116 if there is a change to the electricity provision contractfrom the corresponding unit 104. Configuration manager 208 furtherprovides IP addresses to gateways 126 and meters 116 through DHCP server214.

FIG. 2B provides details on process flow for modules in FIG. 2A. Meter116 may transmit a message on the power line network in system 100towards head end 118. This message will be received by gateway 126. Ingateway 126, process 222 analyzes the powerline signal and extracts themessage contents therefrom, which is then converted into a digitalsignal. In process 224, gateway 126 transmits the digital signal to aswitching module in gateway 126 which then connects to a designatedport, for example, an Ethernet port. In process 226, the digital signalis forwarded to an Ethernet transceiver which in turn linked to anupload port. Preferably, triggering parameters in the switching modulecan be set so that notable packet/information are switched to aninternal CPU 228 for further processing. For example the controlcommands which are specific to gateway 126 may be provided.

Communications between meter 116 and system 100 are provided through ahybrid push and pull messaging system. At head end 118, a server firstgroups the connected meters into a series of smaller sub-networks ofmeters. Each sub-network is identified as a BPL segment. Meters in asegment may be linked by location, type, assigned owner (e.g. meters forthe same company), etc. An exemplary BPL segment may include all meters116 and BPL nodes connected after distribution transformer 112, as perLV network 110. The server has data relating to its load index, whichprovides a maximum figure for how many meters the server can communicatewith simultaneously or within a certain time period without beingoverloaded. The index may be provided to the system by the operator. Ifthe number of messages exceeds the index for that time period, theserver may not be able to process messages that are received in a timelymanner. The load index may be set to different values depending oncertain conditions, such as the current time, day, season, networkconditions etc. A range of index values and conditions may be providedand the system may select an appropriate index for the currentconditions of system 100 and/or its environment. Based on the loadindex, the server calculates how many BPL segments that it cancommunicate with simultaneously once it starts to retrieve meter datafrom system 100. For example, consider a system where there are 1000 BPLsegments, where each BPL segment sub-network has 200 meters and the loadindex is set to be a maximum of 2000 meter readings simultaneously. Withthat index, the server can communicate with 10 BPLs simultaneously (10BPLs×200 meters/BPL=the load index). The server selects a first set of10 BPL segments and sends one broadcast message to each selected BPLsegment. As such, the server sends a block of messages to the selectedBPL segments. The selection of the BPLs can be made on any basis,including random, proximity to the server, number of meters in the BPLs,power draws for the BPLs, etc. Upon receiving a broadcast message,meters 116 in the first set of BPLs that receive the message treat itsreceipt as an indication that the server is available to receive datafrom the meter. As such, at that instance, it is possible that the 2000meters (10 BPLs×200 meters/BPL) may collectively all attempt to pushtheir messages to the server at around the same time.

Each meter 116 may send (or “push”) one or more messages to the server.Each meter may have a data queue which stores its pending meter profiledata to be transmitted. When the server sends a message to meters 116that it is available to receive data, meters 116 can deplete their dataqueues and send one or more meter profile responses to the serverdepending on how much data is in the queue waiting to be sent. Once thequeue is depleted, meter 116 will send an end of message to notify theserver it has no more data to send.

In the above scenario, when the server has received responses (expectedresponses) from the initial 10 BPL segments (which would provide a totalpossible 10×200=2000 simultaneous replies, which does not exceed theload index of 2000), the server can send an additional broadcast to anext segment (i.e. an identified 11th BPL segment) to continue with itssystem readings. The server at head end 118 sends additional broadcastmessages to additional BPL segments as long as the net maximum number ofoutstanding requests is below 1800 (as 200 responses have beenreceived). For example, in a broadcast scenario for a server having aload index of 2000, consider a situation where after one minute ofsending 10 broadcast messages to a total of 2000 meters, the serverreceives 20 replies from each segment, i.e. 20 replies from 10segments=200 replies. While the server is waiting for the remaining 1800meters (2000−10×20) to reply, the server can also send an additionalbroadcast message to an 11^(th) segment to initiate that responses frommeters in that segment, since it has 200 meters and the cumulativeoutstanding replies would be 1800+200=2000, which is still within theload limit. If there is another BPL segment that has more than 200meters, then if that BPL segment is selected, there is a risk that theserver may be overloaded with responses as the index will be exceeded.If there is another BPL segment that has less than 200 meters, then ifthat BPL segment is selected, the server will not be overloaded withresponses as the index will not be exceeded. This process and algorithmattempts to maintain an as-full-as-possible message throughput count forthe system to be as close as possible to the load index (here 2000messages). In another embodiment, the server may wait until it hasreceived responses from all or substantially all, responses from theinitial broadcast (e.g. from the 2000 requests) before sending a secondbroadcast (e.g. to a second 2000 meters).

In summary, an embodiment provides a method for communicating messagesfrom the server, at a central location, to a plurality of meters in thepower network. From the central location, an embodiment obtains statusupdates from the meters modules by transmitting broadcast messages to afirst network, such as MV network 108, destined for delivery to metersin LV networks 110. The broadcast messages are transmitted in a block ofmessages, with a portion of the broadcast messages sent to a particularLV network 110. An embodiment will monitor for responses to thebroadcast messages from meters in the particular network. An embodimentwill transmit a second set of broadcast messages for delivery to a LVnetwork 110, when said responses to the broadcast messages at leastmatch the size of the second set, i.e. the number of targeted meters inthe second set is not bigger than the number of responses received. Thetotal number of meters expected to provide responses to the initialblock of messages transmitted is less than the current load index forthe server.

Additional features are provided for monitoring and managing messageresponses. During message polling, there may be meters 116 thatexperience poor connectivity to system 100. This may result in somemeters 116 not receiving the broadcast message and/or the loss of pusheddata from meters 116 before reaching the server. An embodiment providesthresholds and monitors for the server to identify any such situation. Aresponse to the situation is to trigger a re-broadcast message from theserver. For example, a server may be expecting meters from a particulara BPL segment to push message to it, but the server subsequentlydetermines that a certain number of meters 116 in the segment did notreply with data or end of message. In response, the server canre-broadcast the meter reading available message to the BPL segment. Thenumber of meters can be set to a set number or percentage (e.g. 10%non-responsive). If the server expects meters in a BPL segment to push amessage, but if a higher number of meters have replied, then instead ofre-broadcasting a request message to all meters 116, the server maytransmit a unicast message to send individual meters to indicate thatthe server is available to receive data. The higher number may be set asa static value or as a percentage of non-responses (e.g. between 0 and10%). The message may be unicast multiple times to the non-responsivemeters. If a meter still does not reply with any message after sendingunicast message, the server may declare that this meter is not reachableat present and may remove that meter from the current data retrievalloop. Subsequent data retrieval efforts may be made to that meter at alater data collection interval.

Using a strictly push mechanism can increase the efficiency of readingsand also significantly reduce data latency. However in a massive meternetwork, a strictly push system can overload the server with messages. Ahybrid push/pull message system as noted above allows the server tocontrol the expected load and have the efficiency and reduced responsetime of a push network. For an embodiment, as opposed to permitting allmeters 116 in system 100 to push their data independently into system100, an embodiment provides groups of meters 116 (as segments) to pushdata to system 100 at distinct instances of time. It can be seen as anetwork-wide time division multiple transmission system. A data pullmechanism by the server enables the server to send messages to meters116 for specific reports. A data push mechanism allows meters 116 torespond to such messages asynchronously when the request is received. Assuch, there is an initial time-regulated set of messages that pull fordata by the server and (time unregulated) pushes of responses frommeters 116 as the messages are received.

FIG. 3A provides further details on a remote meter reading processes asused in meter 116. As previously noted, meter 116 provides telemetricson devices in unit 104 to head end 118. Meter 116 may be embedded into atraditional exterior meter connected to a power feed from LV network 114that connects to unit 104 associated with meter 116. Meter 116 may alsobe provided as a standalone computer, a laptop computer, a mainframecomputer, a cellular telephone or another device having suchcomputer-based components. Meter 116 communicates through data sent andreceived through powerlines, but meter 116 may also communicate withhead end 118 through an internet connection, a wireless internetconnection, a WiFi connection, an Ethernet connection or any otherconnection protocols and systems known to a person of skill in the art.

Meter 116 comprises communication module 128 and meter module 130.Communication module 128 generates and processes outbound communicationsfrom meter 116 to network 114 and receives and processes inboundcommunications received over network 114. Communications can be sent toexternal devices, such as head end 118, a device at substation 114and/or gateway 126. Communications can be ultimately addressed any ofsuch external devices. Meter module 130 is a meter connected to a powerfeed to provide power usage measurement and other electricity relateddata. Communication module 128 is connected to meter module 130 througha serial universal asynchronous receiver/transmitter (“UART”) interface,although other communication links can be provided.

One embodiment of communication module 128 comprises request managermodule 302, schedule manager module 304, event manager module 306, andplatform interface 308. Request manager module 302 receives messagesfrom head end 118 through the network of system 100 and processes them.In one embodiment, simple network management protocol (“SNMP”) is usedand request manager module 302 accepts or sends requests from head end118, and processes them accordingly. Requests from head end 118 may begrouped into two categories:

1. Requests that require interaction with meter module 130; and

2. Requests that can be processed without interaction with meter module130.

Upon receiving requests in the first category, request manager module302 sends a command to meter module 130 immediately and sends a responsefrom meter module 130 back to head end 118. For the second type ofrequests, request manager module 302 will process the requestimmediately. If processing a request results in the occurrence of anevent that needs to be recorded, request manager module 302 may store amessage in an event message queue. The message queue used to pass datafrom request manager module 302 to schedule manager module 304, there isa corresponding queue which passes data in reverse. In one embodiment,messages between each module in meter 116 can be exchanged in asynchronized transfer scheme. Processes and modules in meter 116 mayfunction on an event based system (such as a state machine).

Schedule manager module 304 executes schedule tasks at predefined time.The schedule manager module may maintain a schedule for the tasks andmay generate reading commands according to the schedule. Exemplary tasksinclude performing:

-   -   Clock synchronization of the meter's clock to a global time for        the system (i.e. a system time), which may be maintained by at        head end 118;    -   Rate switching, where different power rates can be applied to        calculating power usage according to a schedule which may change        rates for different times of the day/week/month/year;    -   Periodic meter reads of meter module 130; and/or    -   Periodic meter event detection.        Schedule manager module 304 also generates signals which can be        used by a power regulator/diverter to regulate the amount of        power to provide a fraction of power (any value between 0% and        100%) of the available power on the transmission line that can        be provided to the related unit 104. In one embodiment, module        304 provides signals that either allow power to be provided to        its unit 104 or disconnect unit 104 from the power in network        110 by controlling the physical connection to the power through        a relay in meter 116. As such one component of schedule manager        module 304 is a connection management module (not shown). The        connection management module may be provided as part of or as a        separate module to schedule manager module 304. The connection        manager module may evaluate readings and data relating to past        power usage at the site and generate connection signals for the        meter to the power transmission system in view of the readings.

In determining whether or not to connect or disconnect unit 104 from thepower, a set of one or more conditions/thresholds may be monitored bymodule 304. The conditions may relate to operating conditions of network110, meter 116 and/or unit 104. The conditions may include a thresholdparameter. For unit 104, operating conditions and thresholds may includea maximum (or minimum) amount of power drawn (in watts) and a thresholdof power drawn over a window of time (e.g. during a peak consumptionperiod, during rush hour, in a morning time window, etc.) As such,manager module 304 provides a software “fuse” function that can betriggered to limit the amount of power provided to unit 104. When thesoftware fuse is not “blown”, a connection to the power for meter 116 ismaintained. When the software fuse is “blown”, the connection to thepower for meter 116 is broken. The software fuse setting can be set andreset according to conditions detected by meter 116. The conditions andparameters may be provided directly to unit 104 and/or module 304 by auser or through management software at head end 118. Thisconnection/disconnection function may be provided in a separate modulein meter 116.

In operation, schedule manager module 304 may periodically send acommand to meter 116 to obtain a reading of the current amperage drawn(in amps) and a power reading and convert the figures into a powerreading (in watts). The data may be stored to a memory by module 304.Module 304 may send period and/or continual commands on certainintervals (e.g. every 1-20 minutes, once a day, etc.) until a thresholdis reached (e.g. 100 readings, a set of readings has been obtained forthe peak hours). As one exemplary threshold, if the total current orpower reading for a period exceeds a related threshold, then a triggercondition is set to schedule manager module 304 send a command toplatform interface 308, which in turn send a command to module 132 todisconnect the relay of meter's power output from the power line. Thisfunction acts as a software fuse configurable by an applicationoperating at head end 118. A reset of the parameters for the fuse (e.g.a restart of the monitoring of the trigger conditions) may be providedby a message sent to meter 116 through a switch on meter 116.

Event manager module 306 periodically checks if a new event is providedto the event message queue. In one embodiment, for each new event in theevent message queue, event manager module 306 may generate and send aSNMP trap (i.e. a message) to notify head end 118 of any new eventsdetected by meter module 130. When multiple events are triggered, eventmanager module 306 stores records of the events in a memory queue andsends the earliest event to head end 118. When head end 118 provides areply acknowledging this event, the next earliest event is then sent tohead end 118. If no reply to a first transmission of an event isreceived within a first timeout period, event manager module 306attempts a second transmission. If no reply to the second transmissionof an event is received within a second timeout period, event managermodule 306 attempts a third transmission. If no reply to the thirdtransmission within third a timeout period, the event manager may entera loop to retry transmissions periodically. In one embodiment, the firsttimeout period is less than the second timeout period, which is lessthan the third timeout period. However, different values for the timeoutperiods and the number of timeout periods can be provided.

Platform interface 308 translates commands from other modules ofcommunication module 128. Platform interface 308 receives messages fromrequest manager module 302 and schedule manager module 303. In case of areal time request, such as disconnect request or on demand read request,request manager module 302 forward these messages to platform interface308 for data communication to meter module 130. In case of a scheduledperiodic meter read, schedule manager module 304 will send a message toplatform interface 308 for data retrieval. In one embodiment, platforminterface 308 translates the commands to IEC 62056-21 compliant commandsfor use by meter module 130. It also parses raw meter readout intomessages and profiles for other modules of communication module 128.

Through the modules of meter 116, remote and scheduled processes can beexecuted including scheduled recording and/or transmission of meterdata, controlling and programming data recordal rates for meter 116,selective connection and disconnection controls for meter 116 to thepower line and evaluation and reaction to configurable detectedthresholds on the meter data, including generation of real time eventnotifications based on the data analysis.

In one embodiment, processes are implemented in a communication chipsetof meter 116, which allows shared data and memory access. Meterintelligence software operating on the chipset can provide direct accessfrom the communication protocol of the transmission system to the dataof meter 116, thereby eliminating a protocol translation which can bepresent when data is exchanged between two chipsets.

When a meter reading request is received from system 100, metercommunication module receives this message, within the same operatingsystem in the chipset, it obtains the requested data from its memory andgenerates and sends a response to system 100.

When a meter control message is received from system 100, a metercommunication module in meter 116 receives this message and meter 116can conduct internal data validation, make calculations on the data,generate commands for meter 116 and provide responses and messages afterperforming these operations.

The communication module has schedulers which can periodically evaluatea set of pre-set conditions. Upon detection of an anomaly, it can send amessage to a pre-defined central server software.

Now, further detail is provided on a power management feature in meter116. FIG. 3B illustrates power features for meter 116. AC power 310first passes through rectifier 312, which converts alternating current(AC) power to direct current (DC) power module 314. DC module 314 passesthe converted power signal through switching regulator 316, which lowersthe voltage and provides the output to the secondary DC module 318,which supplies power to meter 116. Capacitor 320 is connected at theoutput of rectifier 312. Capacitor 320 will have ancillary componentsand circuits connected to it (not shown). The size of capacitor 320 canbe selected to be a sufficient size to store a charge that can bedissipated to meter 116 to provide sufficient temporary power to same.In this embodiment, the capacitor is 100 uf. Other capacitor values upto 1 f may be used. A bank of capacitors (having the same or differentvalues may be used). A discharge resistor network (not shown) can beconnected to capacitor 320 to provide a suitable discharge pattern forregulator 316. A voltage switching circuit (not shown) can be connectedto capacitor 320 to provide a charging signal for capacitor 320. Valuesfor the resistors in the network can be selected to provide differentdischarge rates. Capacitor 320 provides a power reserve and is connectedto primary DC module 314. In one embodiment, capacitor 320 provides avoltage reserve of approximately 450V (for a meter connected to a 240 VAC line). When AC power 310 is operating normally, capacitor 320receives the voltage applied to it and stores the energy. The storedenergy has a voltage equal to the output voltage of primary DC module314. When AC power module 310 lost AC input or is de-activated (e.g.through a power outage), capacitor 320 discharges its stored energy intoswitching regulator 316 until its voltage is lower than the minimuminput voltage of switching regulator 316. Due to the nature of theresistor/capacitor network the discharge to regulator 316 occursautomatically as the output from rectifier 312 drops below the chargestored in capacitor 320. Switching regulator 316 has a wide inputvoltage range. However, the minimum acceptable voltage for its input isgenerally much lower than the nominal value of the primary DC module314. Energy stored in capacitor 320 is proportional to the voltage ofprimary DC module 314 squared. As such, an exemplary 85% drop(approximate value based on European homes) in the voltage of capacitor320 indicates 98% efficiency in energy. For example, in this embodiment,if the AC input is 240 VAC, then the DC primary would be 240VAC×√{square root over (2)}=339 VDC. The lowest input voltage thatshould be provided for meter 116 is 35 VAC, which is 35 VAC×√{squareroot over (2)}=50 VDC. A voltage drop of 1−35/240=85% can produce anenergy depletion of (339²−50²)/339²=98% efficiency in the capacitor. Thereserve energy in capacitor 320 is able to dissipate and supplyappropriate power to the meter's circuits and components. Comparablecalculations and capacitor values can be provided for meters that areconnected different voltage line signals, such as 110, 100 and 120 ACvoltage lines.

In other embodiments a secondary voltage supply can be provided in lieuof or in addition to capacitor 320. Such secondary voltage supply can bea battery, such as a rechargeable battery.

In other embodiments, capacitor 320 (and its related charging anddischarging circuits) may be located between switching regulator 316 andsecondary DC module 318. In other embodiments, multiple capacitorsand/or secondary voltage supplies can be provided at any locations inFIG. 3B.

Capacitor 320 is provided to ensure that a continuous supply power isprovided to meter 116, in the event of a power failure. The energyprovided from capacitor 320 is not meant to provide long term power—itspower reserve is in the order of several seconds. In this dischargetime, meter 116 is provided with enough time to recognize that a powerfailure condition has occurred to enable it to send a notificationmessage to head end 118 to indicate such power failure. Meter 116contains an AC sensor circuit (not shown), which detects an AC signalloss and triggers release of signal to an input/output channel for theCPU of meter 116, which can then be detected by meter 116. When AC powerfails, capacitor 320 discharges its stored voltage to regulator 316. Ascapacitor 320 depletes its energy, its voltage also drop accordingly,eventually dropping to 0 V, thereby exhausting its stored energy. Whenthe voltage has dropped to a certain level, capacitor 320 cannot provideenergy to support meter 116's normal operation. A voltage thresholdcircuit (not shown) is provided to detect when the voltage output ofcapacitor 320 drops below a threshold and generates a signal. The signalcan be used by meter 116 to generate a “last gasp” message that is sentto head end 118. At such an instance, meter 116 will shut down shortlythereafter. Having a high voltage, which in one embodiment is 450V, onprimary DC circuit 314 provides a large power reserve margin beforecapacitor 320 discharges to the minimum acceptable power input level,thereby tending to maximize the time that capacitor 320 provides usefulenergy to meter 116.

BPL technology utilizes a data spectrum transmission bandwidth ofapproximately 2 MHz to 30 MHz. This range of frequency spectrum can beused to couple between a large discontinuity gap in a physical line aslong as the physical line from the discontinued points are larger than awavelength of the respective frequency. This bandwidth has a couplingaffect in RF transmission. Using such bandwidth will allow RF signal to“jump over” broken wires. As such, when an LV power line is cut or afuse in the connection is broken, the discontinuity that has been formedcan be traversed as the BPL signal can still bridge and “jump over” thephysical discontinuity and keep the link alive. This provides a lateopportunity to send a “last gasp” message from meter 116 to advise headend 118 that meter 116 has lost power. Often when a MV or LV faultoccurs, the connection points of different type of equipment may appearto have a discontinuity of in the related transmission system (e.g. abreak in a power line). The discontinuity may be present anywhere in LVnetwork 110. The size in a discontinuity can be typically several mm toseveral dm in length. The powerline carrier for messages for anembodiment which is provided in approximately the 2 MHz to 30 MHz rangein most cases can cross over such discontinuity and still establish alink. As such, while power signals may be lost, the discontinuity maynot block the RF link as long as the wire on each side of thediscontinued points are longer than one wavelength of the respectivefrequency. This allows meter 116 to use its reserve power drawn fromcapacitor 320 to generate and send a “last gasp” message to cross thebreaking point towards head end 118 and notify such power service outageevent. As such, messages from meter 116 that are carried on a carrierfrequency of between approximately 2 MHz and 30 MHz are preferablygenerated and used.

Next, details are provided on meter connection/disconnection processesused by an embodiment of system 100. Specifically, meter 116 is equippedwith an electricity connector/disconnector module that can be controlledboth locally and remotely to completely disconnect and connectelectrical supply at the location associated with unit 104.

FIG. 4 illustrates one embodiment of the remote and localconnect/disconnect functions of meter 116. The functions comprise thefollowing processes:

-   -   1. Through head end 118, head end client 204 initiates one of        the four remote control actions (remote connect, remote        disconnect, enable local button control and disable local button        control) and sends it to configuration manager 208;    -   2. When configuration manager module 208 receives action, it        validates the action, parses it into a corresponding SNMP set        command, and then sends the request to through the network of        system 100 to request manager module 302 of communication module        128 of meter 116;    -   3. Request manager module 302 will validate the data format and        data content sent by configuration manager 206, and then        forwards it to platform interface 308 upon validation; and    -   4. Platform interface module 308 validates the action received        from requester manager module 302 and translates it into a        meter-acceptable command, and then sends it to meter module 130        through a serial port.

Sub-modules may be provided in platform interface module 308, includingdisconnect manager module 308(a), which implements a disconnectorcontrol flow. Disconnector manager module 308(a) may be activated athead end client 204 through its GUI, from a remote control command sentfrom head end client 204 and/or automatically from head end 118.

In one embodiment disconnect manager module 308(a) utilizes a statemachine for processes to transition among connected, disconnected andtransition states. An exemplary state machine has four states andaccepts four remote actions plus one local action to navigate throughthe states. Table A shows the four states and their correspondingmeanings.

TABLE A Local control Remote control States Premises enabled enabledConnected Connected No Yes Disconnected Disconnected No YesReady_to_disconnect Connected Yes Yes Ready_to_connect Disconnected YesYes

FIG. 5 illustrates a state machine implemented by disconnect managermodule 308 and the state transition of the disconnector control. Twostates 502 and 504 indicate that the disconnect manager is connected tohead end 118; two states 506 and 508 indicate that disconnect manager isdisconnected from head end 118. The digits and arrows around each stateare showing how each state can transit to others states. As noted,actions 1-5 are shown which provide exemplary stimuli to transit betweenstates. Actions 1-5 include: 1) Collect data immediately; 2) Disconnectimmediately; 3) Enable local control; 4) Disable local control; and 5)Button pressed.

Head end client 204 can remotely send commands to disconnect managermodule 308(a) by sending a request to meter 116 to disconnect, connect,enable or disable local button control immediately. In one embodiment,to allow an operator to perform a local control of meter 116, a localsignal in the GUI is first enabled by head end client 204 through a SNMPset command. Once local control at meter 116 has been enabled,disconnection or connection of meter 116 to the LV network 110 isdictated by the operator at meter 116. In one embodiment, a safetyfunction is implemented at meter 116 that requires the operator to holda switch on meter 116 for a predetermined time (e.g. ten seconds ormore), to prevents the operator from disabling button unintentionally.In one embodiment, such switch is a button. Disconnector manager module308(a) in platform interface 308 will initiate a message and push itinto event message queue to trigger an SNMP trap to be sent to head end118 whenever there is an occurrence of disconnector control statetransition meter 116.

A meter disconnector status register implemented at meter 116 containsthe information to indicate whether end unit 104 is connected ordisconnected. In one embodiment, at communication module 128 of meter116, the status of disconnect manager module 308(a) is stored in the RAM322, and updated after every switching action of an electrical service.Meter 116 can be cut from a service of a customer and also canre-connect to the service of the customer by using a mechanical relay inmeter 116 to the physical power connection related to the service.Multiple relays may be provided to provide stages of power to the meter.On boot-up, disconnect manager module 308(a) reads out the status of thedisconnector from meter module 130, and compares it with the statusstored in RAM 322 at communication module 128. Any discrepancy of thedisconnector status will be reported to head end 118. In one embodiment,such reporting is done through a SNMP trap.

In one embodiment, meter 116 further comprises automatic control filtersfor protection of meter 116 and the electrical devices behind meter 116,including any smart devices 136, when one of the following conditionsare detected:

-   -   1. Over-voltage;    -   2. Over-current; and/or    -   3. Meter tampering (e.g. opening of the case of the meter,        unauthorized disconnection from power supply, etc.).

Over-voltage detection and reaction is provided in disconnect managermodule 308(a) to prevent a high voltage signal from reaching anddamaging meter 116 and connected electrical devices. In one embodiment,this over-voltage control function is provided through a configurablevoltage threshold circuit and a decision stage built in the automaticvoltage control filter 308(b). Automatic voltage control filter 308(b)polls a register value for meter 128 to monitor the voltage at the endunit 104. When automatic voltage control filter 312 detects a voltage atend unit 104 that is greater than a threshold, automatic voltage controlfilter 308(b) will initiate a disconnect command through disconnectmanger 308(a), which in turn will send a disconnect command to metermodule 128 through the serial port. Then disconnector will cause endunit 104 to be disconnected immediately from LV network 110 to protectmeter 116 and electrical devices/components behind meter 116.

Over-current detection and reaction is provided in disconnect managermodule 308(a) to prevent high current and short circuit from damagingmeter 116 and downstream electrical devices. In one embodiment, anautomatic current control filter 306(a) is provided in event managermodule 306. A detected current can be evaluated to determine whether ashort-circuit condition exists for meter 116. The automatic currentcontrol filter can read the electric current values of end unit 104 asmeasured by meter module 130 and identify any immediate increase ofload. Upon detection of a sudden increase of electrical current whichexceeds a maximum rated value or a configured value for a configuredperiod of time, automatic current control filter 306(a) will maintainpolling of the meter register value to monitor the current over the endunit 104. Once the current over end unit 104 is greater than aprescribed threshold, automatic current control filter 306(a) willinitiate a disconnect command and send it to disconnect manger 308(a),which in turn will send a disconnect command to meter module 130 throughthe serial port. The disconnect manager module 308(a) will cause endunit 104 to be disconnected immediately from the LV network 110 toprevent further damage to its connected device 134.

In one embodiment, meter disconnect status integrity validation is builtin to a meter disconnect status filter 306(b) residing in event managermodule 306. The meter disconnect status filter 306(b) will re-disconnectmeter 116 when meter 116 was inappropriately re-connected as a result ofactions by persons at unit 104, such as tampering of the meter by anowner of premises. Upon meter 116 rebooting after reconnection, meterdisconnect status filter 308(a) will keep polling the meter disconnectorregister value in the meter module 130 and compare it with the statusstored in RAM 322 and in database 220. If the wrong connection statushas been detected at the meter module 130, the meter disconnect statusfilter 306(b) will initiate a disconnect command and send it to meterthrough the serial port, and send it to disconnect manger 308(a), whichin turn will send a disconnect command to meter module 130 through theserial port. Disconnect manager module 308(a) will cause the unit 104 tobe disconnected immediately from the LV network 110. The meterdisconnect status filter will also created a message, concurrently orwith delay, and push it into the event message queue to trigger an SNMPtrap to be sent to head end 118. A sensor can also be provided to detectwhen a case (i.e. a housing) for meter 116 has been opened. Comparablemessages can be provided to LV network 110 upon the detection of anevent indicating tampering of meter 116.

In one embodiment of system 100, a cluster control supports connect ordisconnect of meter 116 within an associated subnet simultaneously. Thecluster control uses the advantages of an AMI system built uponcommunication network using BPL technology. With the broadbandnetworking and TCP/IP built in, head end client 204 can send a broadcastmessage to a specific subnet and disconnect manager module 308(a) ineach meter 116 can accept the broadcast message and perform the actionin accordance with the broadcast message. The cluster control improvesthe disconnector control performance and efficiency for the wholemanagement of system 100. In one embodiment, a broadcast requestingdisconnect or reconnect of units 104 is achieved by sending a broadcastSNMP message to an IP subnet. An IP subnet corresponding to a group ofunits 104 is often connected on the distribution transformer 112. Thebroadcast message will reach every meter 116 in a subnet andacknowledged by the request manager module 302. The request managermodule 302 then will send a message to the platform interface 308 whichin turn will relay the disconnect command through the serial port tometer module 130.

To trace control actions for audit purposes, platform interface 308records each disconnector transition into a log file and synchronizesthe log file with head end 118 periodically.

The utilization of BPL technology and the network infrastructureimplementation allows system 100 to perform with greater efficienciesthrough the ability of collecting data and pushing instructions tometers 116 in parallel. The remote disconnect/reconnect functionalityalso allows an embodiment to control each individual meter 116 in thesystem and to provide security of the power feeds to end users at units104. The remote disconnect function also allows rapid response to anypotential problems to meters 116 and the end users.

One embodiment of system 100 further comprises periodic meter readingprocesses. In one embodiment, head end 118 performs two metering datapulling actions based on preconfigured intervals.

Communication module 128 in meter 116 periodically reads out all meterregister values from meter module 130, constructs a profile entry usingall the register values, and stores the profile entry in a profile fileon its memory. In one embodiment, the memory of communication 128 is RAM322. In one embodiment, the default polling interval is 15 minutes. Inanother embodiment, the interval can be set a given time interval (e.g.a multiple of 15 minutes) by head end 118. The same polling interval isused for all meters 116 managed by head end 118. Head end 118 providesbatch configuration functionality instruction to push a new pollinginterval along with its activation time to all meters 116 managed by anembodiment. At the activation time, all meters 116 in system 100implement the new polling interval without the intervention of head end118.

System 100 provides a reliable method of collecting periodic usage anddata updates from the entire AMI system, at regular and adjustableintervals. To facilitate this process, meters 116 support the setting ofdata collection intervals and the sending usage and data updates back tohead end 118 at the specified interval. NQM 206 controls when and how topull meter data. Within meter 116, event manager module 304 responds tothe request from NQM 206.

Head end 118 periodically polls metering profile data from all relevantmeters 116, and stores data in database 220. Head end 118 performs dataconsistency checks to guarantee that correct data is retrieved andstored, in-order and without gaps or missing data. This requiresintelligent logic at both the head end and meter.

FIG. 6 shows an embodiment of the meter reading function of head end118, where basic functions are to set parameters for a collectionprocess, collect data periodically, process data for integrity, processthe raw meter data, save meter data and provide the data to the system.

First, NQM 206 in head end 118 sends a request to each meter 116 toobtain data. In doing so, it may send a broadcast message or a multiplemessages in parallel to all meters 116 or a group of meters 116 thatcommunicate with gateway 126, to retrieve meter data simultaneously.This timing is facilitated by the network architecture of system 100 andits BPL gateways and by applying a networking protocol combined with anIP switched network support using BPL technology. In one embodiment, thenetworking protocol used is the SNMP protocol. This network architectureallows retrieval of data from meters 116 at high speeds so as to permitreal time monitoring of the meters 116.

An embodiment of system 100 implements data requests and read throughnetwork commands sent over the network in system 100. A network readcommand is implemented by having NQM 206 send a broadcast or multiplemessages for data query to the meters 116. The request manager module302 in each meter 116 will then retrieve appropriate meter data storedin its database for a scheduled data retrieval request or relay therequest to platform interface 308 to obtain instant meter data, and thensend these data back to NQM 206. NQM 206 receives all meter data andstores the data in a queue and process each retrieve to a standardformat and store this information into database 220. NQM 206 alsoautomatically fills in any missing meter readings after a period ofnetwork failure or down time of head end 118.

In one embodiment, system 100 collects and stores meter data at periodicintervals (e.g. every 5, 10, 15, 60, 120 minutes or other intervals)from each meter 116 in network. This interval is configurable. Theoperator can set the data collection interval in head end client 204 ofhead end 118 (FIG. 2). From there, head end 118 sends updated datacollection interval to each meter 116 in the network 100 and stores thedata in database 220 as well.

In one embodiment, a profile file in meter 116 is provided. In oneembodiment, the profile stores up to approximately 5000 profile entries,stored in the order they are received. In another embodiment, theprofile file may also be organized as a circular buffer where once thebuffer is full, the oldest entry may be overwritten by the most recentone. For the embodiment with a default interval of 15 minutes, meter 116can store 52 days worth of data collected from the meter module 130.Changing the data collection interval will increase or decrease thelength of time for which a meter can store data. The data may be storedin RAM 312.

FIG. 7 shows details of state machine 700 provided at head end 118 formanaging periodic meter reading of meters 116. In one embodiment, theperiodic meter reading module has six states and accepts seven actions,namely:

-   -   1. The state machine starts in idle state 702.    -   2. The state machine stays in idle state 702 until either one of        two events happen: the scheduled read at the next time interval        is due or the last read data index value is less than the        “newest available” index reported by the meter. When either of        these events happens, state machine 700 moves to Check Meter        Data Integrity state 704.    -   3. In state 704, head end checks database records for gaps, and        retrieves the last read data index for the associated meter.        Gaps can be detected because the data index are in sequence.        When NQM 206 requests meter 116 to provide data, meter 116        informs NQM 206 of the next sequence number to pull and how many        data sequence numbers it contains after the first pulling. In        case meter 116 has more than one sequence of data, NQM 206 can        recognize that multiple data records from this meter should be        expected. Then, it sends a request to change the meter's        data-read index pointer to the desired record. The pointer is        used to track the sequence number. Finally, it sends a request        to meter 116 to retrieve the data record and moves to “Get Meter        Data” state 706.    -   4. The state machine receives the requested data record with the        index of the “newest available” record on the meter, which is        stored in database 220. The state machine then moves to “Process        Meter Data” state 708.    -   5. In state 708, head end 118 analyzes the retrieved meter data        record for integrity and correctness, extracts the data into a        format useful to the rest of head end system 118, writes the        record to database 220, and updates the last read data index.    -   6. The state machine moves to the “Reply Client” state 710.    -   7. The state machine informs head end 118 of the retrieved data,        and moves back to Idle state 702, ready to start the meter data        collection procedure over again.

This series of states allows head end 118 to automatically retrieve anyrecords it has not yet retrieved due to connection failure, startingwith the oldest record first. Doing so maintains a consistent, completecopy of all read meter data at head end 118.

If at any time a state machine spends more than a specified amount oftime in a given state, it logs an error and returns to “Idle” state 702.Also, if in any state in state machine 700 encounters an error, (such asmalformed or incorrect data), state machine 700 returns to Idle state702. This ensures that requested data is retrieved, analyzed to becorrect, processed and stored.

The periodic meter reading goes through the “Idle”, “Check meter dateintegrity”, “Get meter data”, “Process meter data”, and “Reply client”states to complete a reading task. However, it goes to “Error handling”state 712 if an error event occurred. Using this error handlingmechanism ensures that the error or exception does not suspend thisfunctionality. As noted in FIG. 7, actions 1-7 indicate exemplaryactions that initiate transitions between states. The states include: 1)Start meter data collection; 2) Start getting meter data; 3) Startprocessing meter data; 4) Start reply to client; 5) Finish all tasks; 6)Error controls; and 7) Waiting.

Now, further detail is provided in FIG. 8 on a timeline of messagesbetween head end 118 and meters 116 for periodic meter readingconfiguration setting:

-   -   1. The values of meter data periodic reading configuration in        head end client 204 are set up.    -   2. Head end client 204 sends head end configuration values to        NQM 206.    -   3. A communication server processes the request from head end        client 204, compared with values of current configuration.    -   4. If the configuration values are not same as current        configuration values, the communication server updates the        configuration setting file.    -   5. Head end client sends meter configuration values to        communication server.    -   6. The communication server sends requests to all meters 116 in        system 100 to inform that the configuration settings are        updated.    -   7. Meters 116 update their configuration setting and inform        meter module 130.    -   8. Meters 116 send acknowledges back to communication head end        118.    -   9. The communication server then sends a reply to head end        client 204 after updating the configuration settings.

Each meter 116 is responsible for identifying and tracking the status ofits connected device 138. Each meter 116 may establish a local pollingparameter/algorithm to request and track data and status updates fromits devices 138. Meanwhile NQM 206 may establish a separate pollingparameter/algorithm to request and track data and status updates frommeters 116. One query may be to first ask a meter 116 whether or not ithas data relating to devices 134 (or other status messages) to send.Each meter 116 may collect its relevant data and send a package to headend 118. NQM may receive the data and ask followup requests for moredata or confirmation whether the last record was sent. Upon receiving aconfirmation from meter 116 that its last record was sent, the pollingprocess may conclude.

FIG. 9 provides a time line of interactions of head end 118 and meters116 during a periodic meter reading event:

-   -   1. Periodic meter reading schedule is set up in meters 116        according to the configuration setting.    -   2. When the periodic meter interval timer timeout, the periodic        meter reading schedule task is enabled.    -   3. A communication server gets all topology attributes of meters        116 in network.    -   4. The communication server verified the data integrity in        meters 116.    -   5. The communication server sends the set request command to        meters to set the sequence ID.    -   6. The communication server sends the read command to meters 116        to read meter data.    -   7. The communication server analyzes and processes data from        meters 116, saves the meter data into a database.    -   8. The communication server sends response to head end client        204.

In one embodiment, the communication server is NQM 206. The periodicmeter request may go through “Idle”, “Check meter date integrity”, “Getmeter data”, “Process meter data”, and “Reply client” states to completea reading task. An “Error handling” state is entered if an error eventhas been detected.

At head end 118, all of the retrieved data is stored in database 220. Inone embodiment, up to one year's worth of data is stored in the databasefor quick access by an operator. With the data for each meter 116,database 220 also stores the last read data index from each meter 116 inthe network. Head end 118 maintains a finite-state machine for eachmeter 116, which ensures that meter data is properly received, checkedfor integrity, processed and stored.

At meter 116, a table of meter data is stored in flash memory. The dataindex pointer points to the next row from the table that head end 118will request to retrieve; head end client 204 first sets this value, andthen requests the row at that index. Meter 116 reads data independentlyof the requests from head end 118. As such, head end 118 can request anarbitrary record of data from meter 116's table. This configuration alsoallows meter 116 to collect and store data even when connection betweenmeter 116 and head end 118 is lost. Upon re-establishing connection,head end 118 can request the data it is missing, making system 100highly resistant to data loss.

FIG. 10 illustrates a time line of real time processing of certainfunctionalities of an embodiment. The processing functionality involvesmeter module 130, communication module 128, head end 118 and database220.

Meter module 130 comprises a meter status register for recordingabnormal events that occur in meter 116. In one embodiment, the statusregister is a two-byte hex code. Each bit of the hex code is used forone particular event. Upon the occurrence of an abnormal event, thecorresponding bit of the status register is set. The communicationmodule 130 performs the notification function of the exception event.

Schedule manager module 304 of communication module 128 periodicallysends request for meter status to the platform interface 308. Schedulemanager module 304 ensures there is priority of the periodic requests ofmeter status over any other modules in the communication module 128. Inone embodiment where a universal asynchronous receiver transmitter(UART) provides the communication module 130. If the UART port isavailable, schedule manger 304 will lock the UART port to avoid resourcecompetition. Data reads of the meter register value are provided throughplatform interface 308. A data meter protocol, such as IEC62056-21 isused for encoding meter data. After receiving the response from metermodule 130, schedule manager module 304 will unlock UART port to allowuse of the port by other modules which may require access to metermodule 130.

In one embodiment, the read out registers contain the following values,per Table B:

TABLE B Reduced OBIS code Registers C.x.x Status Reading meter code forchannel and rate Kwh Disconnect code On or off Power quality registercode V, A, etc Error or sensor data code Numeric value

In one embodiment, schedule manager module 304 then examines theregister value from the meter module 130 and generates the followingevents:

1. Meter status event;

-   -   i. Terminal cover removed/closed;    -   ii. Strong DC field detected/disappeared;

2. Power quality event;

-   -   i. Voltage drops below the under voltage threshold/voltage        returns to normal after under voltage;    -   ii. Voltage exceeds the over voltage threshold/voltage returns        to normal after over voltage;    -   iii. Power outage of each phase/power return of each phase; or    -   iv. Current exceeds the over current threshold/current drops        below the over current threshold.

The meter status event is generated based on the status register. If abit of the status register changes (which means the meter statuschanges), schedule manager module 304 will check the bit mapping andgenerate the corresponding event.

For every phase, several configurable voltage levels are monitored, suchas an over voltage threshold, an under voltage threshold, and a missingvoltage threshold. If the read-out line voltage exceeds or drops below agiven threshold, schedule manger 304 will generate an event report. Inone embodiment, to avoid unnecessary generation of events due todisturbances or very short voltage dips, a delay mechanism is in placefor voltage monitors. In another embodiment for current monitoring, theover current threshold is monitored.

For each type of event has a unique event code pre-defined for it. Whenschedule manager module 304 detects the abnormal status of meter module130, it will immediately send a message with event code information toevent manager module 306.

Event manager module 306 is in charge of adding more information to theevent message, saving important events to flash memory and also sendingthe event message to head end 118. In one embodiment, the event messageis sent as a SNMP trap.

Information that may be added by event manager module 306 include anidentification (ID) tag, timestamp, and flag to the event messagewhereby:

-   -   1. The ID is used to identify events and will also be used by        head end 118 for event acknowledgement.    -   2. The timestamp indicates the event occurred time.    -   3. The flag indicates if the timestamp of event is valid or not.        This flag is set as invalid if communication module 128 failed        to synchronize its time with NTP server 216. In this situation,        the timestamp in event message will be an estimated system time.

To ensure important events can be recovered after manual power cycle orpower outage, those events that are not acknowledged by head end 118will be saved to the flash memory of meter 116. This mechanism allowsevent manager module 306 to provide notification for all events whenmeter 116 powers on again. In one embodiment, because the lifetime of aflash memory is related to the flash reading and writing times, eventmanager module 306 may use a method to records events into differentpart of a flash to extend the lifetime of the flash memory.

After saving events into flash memory, event manager module 306 willgenerate a message with all the event information as variable bindingsand send the message to head end 118. In one embodiment, the messagesent by event manager module 306 is a SNMP trap. Upon receiving themessage, NQM 206 in head end 118 will send an acknowledgement by usingSNMP set message to the event manager module 306 through request managermodule 302 in communication module 128 of meter 116. The acknowledgementcontains the identification code of the event. If event manager does notreceive the acknowledgement of an event, this event may be resent aftertimeout. This resend mechanism ensures that every event is received byhead end 118 so as to provide notification to the system operator.

In one embodiment, in addition to sending the acknowledgment, NQM 206also checks if the meter event is configured as monitored, records eventin the centralized database server 220, and gives a signal to thegraphical user interface for head end client 220 to trigger an eventdisplay update for all log-in users. There are two configured flags foreach event type in head end 118: one indicates if this type of eventshould be monitored; and the other indicates if the type of event shouldbe notified by using communication methods such as emails, instantmessaging, SMS, or any other rapid messaging methods. For the event typethat is marked as monitored by an operator of head end 118, NQM 206 willcontinue to process it. Otherwise, NQM 206 may just ignore it. Thisfunction provides the flexibility to allow configuration where onlyspecific events are monitored and displayed.

In one embodiment of the head end 118, the following event entries arefound in database 220 for each event, per Table C:

TABLE C Field Description Number A automatically increased number forthis table Event ID The meter event ID Event code The meter event typeEvent source The meter Utility ID Timestamp The time when this meterevent occurred Notified status Indicate if this event has been sent asE-mail Owner The operator who takes the ownership of this meter eventStatus Pending: this process is waiting to be processed Processing: thisevent is under investigation Processed: this event is processed Closed:this event is verified as solved History Record the below informationevery time the event status is changed *the operation time *operatorInformation Other information

NQM 206 is responsible for inserting one entry with the informationretrieved from SNMP trap variable binding such as event ID, Event Code,Event Source and timestamp into database. Other fields of an event entryare used for event management.

When head end client 204 receives an event update from NQM 206, alloperators at head end 118 can see it and start to work on the event. Ifan operator taking the ownership of a meter event, other operators willbe able to see this information by the owner field to avoid conflict.The status field of an event allows clear and easy management of theprogress of the event. The operation history of one event is recorded inhead end 118 for future reference.

In one embodiment of head end 118 is a module called “email” whichretrieves non-notified meter events from database 220 periodically. Forthese non-notified meter events, the email module will compose emailswith event code, event source, and timestamp information and send theemails out to all subscribers and then the notified status of that evententry will be updated by the email module to indicate event notifiedsuccessfully.

The periodic and real time event based processing features of system 100allows significant control over individual meters 116 and allows fasterresponse by system 100 and its operators in the event of localized orsystem wide problems.

Another feature of system 100 provides a clock synchronization featurebetween meters 116 and head end 118.

In this embodiment, meter 116 does not have a battery to maintain itsinternal clock during power outage. An AC regular capacitor provides thepower reserve for only 1 second in event of power outage, and meter 116loses its internal clock if the power outage lasts longer than 1 second.As such, in one embodiment, meter module 130 does not have (or does notuse) a calendar clock. The communication module 128 is, therefore,responsible for all the time-stamped related functions of meter 116.Communication module 128 synchronizes its calendar clock with NTP server216 periodically and upon power restoration. The IP address of NTPserver 216 is stored in RAM 322 of communication module 128, and can beconfigured by head end 118, including through standard SNMP Set command.

When meter 116 initially boots up, communication module 128 tries tosynchronize its clock with NTP server 216. If it fails to synchronizeits clock with NTP server 216, it will enable the clock synchronizationtask.

FIG. 11 illustrates a procedure used by communication module 128 todetermine whether to enable the clock synchronization task at boot-up.

Communication module 128 checks the clock status of the meter module 130on boot-up, once an invalid clock status is found, it will do thefollowing actions in order:

-   -   1 Initiates a clock status invalid message, and then push the        message to event message queue.    -   2. Check if NTP client is enabled, if not, enable it.    -   3. After NTP client has been enabled, start a clock        synchronization task to synchronize clock periodically.    -   4. Activate emergency setting for time of use.    -   5. Disable the rate switching task until clock status has been        changed to valid.    -   6. Make a recode of the profile ID for the last profile entry at        last power down.

FIG. 12 further illustrates the execution of clock synchronization checktask as described in step 3 of FIG. 11.

Upon communication module 128 successfully synchronizing its clock withserver 220, the following actions are executed:

-   -   1. Clock synchronization task is disabled    -   2. Rate switching task is enabled.    -   3. calculate the time difference between the synchronized time        and unsynchronized time (time deviation=the synchronized        time−(the time recorded at last power-down+the time elapsed        since boot-up).    -   4. If the time deviation exceeds certain threshold,        communication module 128 initiates a message with the time        deviation, and then pushes the message to event message queue.    -   5. The timestamps of all profile entries that were captured        since boot-up are adjusted by the time deviation.

In the event of a power down, communication module 128 stores thecurrent clock in RAM 322 immediately. When power is restored, before themeter synchronizes the clock with NTP server 216, the following actionsare executed:

-   -   1. The clock of the meter is calculated as follows: the time        recorded at last power-down+the time elapsed since boot-up.    -   2. A “clock invalid” bit of the module status is set. It remains        active until the clock is synchronized.    -   3. All time stamps that occur before the meter synchronizes with        server 220, are marked as invalid.

The clock synchronization mechanism as implemented in system 100 reducesthe impact of any power outages to data collection and system managementby head end 118.

Now further detail is provided on network analysis features for anembodiment.

System 100 further monitors operating conditions of networks 108 and110. Exemplary monitored conditions include signal to noise ratio(“SNR”) and channel frequency response (“CFR”) monitoring for powersignals carried in networks 108 and 110, as detected at meter 116. SNRmeasures of how much a (power) signal has been corrupted by noise and isdefined by the ratio of signal power to detected noise power whichdisrupting the signal. CFR is a measure of each carrier's sensitivitylevels. It is defined by a gain factor which controls the sensitivity ofa receiver system.

In one embodiment, data is modulated on transmission lines in networks108 and 110 using data division/carrier techniques using differentfrequency bands to define includes multiple carriers. One transmissiontechnology used is Orthogonal Frequency Division Multiplexing (OFDM),which transmits parts of a transmission in a sub channel of a selectedcarrier. A transmission line carries data modulated over a bandwidth offrequencies. For effective bandwidth use, the available bandwidth issegmented into a series of carriers. Each carrier can then carry all orpart of a transmission.

In one transmission protocol, when transmitting a message, head end 118may divide the signal relating to the message in multiple segments andthen transmit each segment on a defined, different frequency range (as achannel) over the available frequency range. At the receiving end, meter116 may extract each message from each channel to reconstitute theoriginal message and then process same. Similarly, when meter 116transmits a message to head end 118, it may divide the signal relatingto that message in multiple segments and then transmit each segment on adefined, different frequency range (as a channel) over the availablefrequency range back to head end 118. In order to prevent communicationconflicts between messages sent downstream from head end 118 to meters116 and messages sent upstream from meters 116 to head end 118 over agiven transmission line in networks 108 and 110, an embodiment mayallocate certain segments of time in a repeating cycle for transmissionof downstream from head end 118 and other segments in the cycle forupstream transmissions. One embodiment provides 1536 carriers for LV andMV networks 110 and 108.

It has been determined that at a given point in system 100, an analysiscan be conducted for signals carried therein. By measuring certainelectrical signals (e.g. voltage, current) at given time intervals overcertain frequency ranges, the electrical signals of messages beingcarried in system 100 can be measured. Depending on the time of themeasurement and messaging timing protocols for system 100, the detectedsignals can represent downstream or upstream messages. Measurements canbe taken at head end 118, meter 116 or points inbetween. At any givenmeasurement point, notional downstream and upstream messages in anormally operating network environment may be expected to have averagemeasured signals of certain values.

Two types of measurements are provided by an embodiment.

SNR is a relative comparative value measuring the quality of a signal toa noise floor. SNR is determined for a particular carrier by measuring apower signal at a location (e.g. meter 116) and dividing it by a noisesignal detected at that location. The noise signal represents part of adestructive radio frequency wave in the transmission. The noise may bein the ambient environment in which that the signal is carried.

CFR is an absolute value measuring the strength of a signal. CFR isdetermined by measuring a power signal at a location (e.g. meter 116).

As noted, measurements may be taken at any point in system 100.Measurements taken at head end 118 may be analyzed by head end 118. Formeasurements taken at elements downstream to head end 118 (e.g. meter116), the data for the measurements may be provided to head end 118 viaa message constructed and sent at the measuring location.

It has been discovered that SNR and CFR are useful data transmissionperformance indicators of and networks 108 and 110 for system 100. SNRand CFR values that tend to decrease (i.e. smaller ratios) indicate aphysical degradation of the underlying electrical medium (namely thepower line in one or both of networks 108 and/or 110).

System 100 addresses several challenges in providing BPL. Some of thetechnical issues that an embodiment may need to overcome include:

-   -   1. Power line cables networks were not originally designed to        carry other data signals.    -   2. Characteristic impedance is unknown and not controlled along        the power lines.    -   3. Power line network topology is unknown and not controlled.    -   4. In general, noise levels in power lines depend on the        external sources and environments.    -   5. Power line network throughput is very sensitive to noise        level. SNR and CFR monitoring features are described in two        sections: SNR and CFR data collection configuration and        performance reports.

As such, in an embodiment, SNR/CFR monitoring and reporting provides oneor more of the following features:

-   -   1. Determine the optimal frequency band and signal injection        location during deployment phase;    -   2. Utilize broadband power line communications and retrieve real        time SNR, CFR data to analyze power line health and trends;    -   3. Analyze and distill SNR/CFR data in a GUI for an operator at        head end 118;    -   4. Provide proactive diagnostics operation; and/or    -   5. Maintain phase to reduce electricity grid cable and/or        component failure.

FIG. 13 illustrates SNR/CFR data collection configuration procedures,completed through head end 118, NQM 206, and communication module 128 ofmeter 116. Configuration processes are started from head end 118. Headend 118, through its head end client 204, allows a user to select theinterval of SNR/CFR data collection, retry times and time out value.Upon selection of the intervals and other data collection requirements,a request with new configuration is sent from head end 118 to meters116. In one embodiment, the request with new configuration settings arereceived by NQM 206 from head end client 206 through socket connectionwrapped in a Qxt framework (trade-mark).

NQM 206 is responsible for writing new settings into a configurationfile, which in one embodiment, is shared by applicable modules of headend 118, NQM 206, configuration manager 208, event manager 210, andinformation request manager (“IRM”) 212. In other embodiments, thesettings files are separate and are written for each module.

Based on the configuration settings, NQM 206 automatically runs SNR/CFRdata collection routines through head end 118 to retrieve data fromcommunication module 128 of meter 116.

Communication module 128 utilizes data collection algorithms to generateSNR and CFR data. SNR data is calculated the ratio of signal and noiseof a carrier. The data may be provided to head end 118 a long row datastring. The string may use SNMP object identifiers to get by NQM 206from communication module 130 and then saved into database 220 server athead end 118. The SNR string can be retrieved from database 220 by headend client 204 and converted to a signal level and graphicallyrepresented in the graphical user interfaces in format of charts,tables, or other visual formats.

FIG. 14 shows one embodiment of the configurability of, SNR and CFR datacollection on client GUI for head end 118. Head end 118 allows users tocan initiate various commands using a GUI at head end client 204,including any of the following:

-   -   1. From which subnets to collect SNR and CFR data. The system        will collect SNR and CFR data from all the devices belonging to        the selected subnets in its BPL networks;    -   2. Frequency of data collection for SNR and CFR data under        normal situations;    -   3. Setting thresholds of SNR and CFR; and/or    -   4. Identifying actions to perform in the event of threshold        violations.

The available actions include:

-   -   1. Send a communication to notice the network administrator;    -   2. Change the SNR and CFR data collection interval; or    -   3. Start data collection on other performance measurements.

In addition to providing data polling for operating conditions of powerlines in networks 108 and/or 110, head end 118 allows a networkadministrator to determine other problems in networks of system 100.

FIG. 15 illustrates one embodiment whereby the user may select SNR/CFRdata by link between slave node and master peer. The SNR/CFR data may bedisplayed in various styles, including two or three dimensional styles.In one embodiment as illustrated in FIG. 16, the SNR and CFR data isdisplayed in a raw table view where the network administrator can clickon any row in the table view to see the chart of SNR and CFR data atcorresponding timeline. The GUI for head end client 204 may providenavigation buttons for user to go through the historical data of SNR andCFR and watch the change of real data and chart display. The changes ofSNR/CFR assist in predicting future trends.

FIG. 17 illustrates exemplary processes steps involved in one embodimentfor predicting trends of characteristics of system 100. The processesinvolve head end client 204 and IRM 212.

After a user select some node and interested link, set up the timerange, and send a request to query SNR/CFR data. A request will throughsocket connection between head end client 204 and IRM 212. IRM 212 willquery database 220 with received the query request. Then, a data set ofSNR and CFR is sent back to head end client 204 if the data query issuccessfully. For the data fetch from the database 220 is row data, headend client 204 needs to transfer those data into database 220 andfrequency and visualized in two dimension styles with time stamp.

The SNR and CFR measurement directly correspond to physical linecharacteristic changes. The rate of change in SNR and CFR values may bemeasured and used to predict line failures. For example, before a lineor equipment on the power line fails, it often emits sparks. Thesesparks can be reflected in SNR and CFR to up and down fluctuations. Bymeasuring the change of SNR and CFR, an embodiment can monitor receivedpower signals and set threshold values to indicate a potential failurecondition. Trends and changes can be determined from comparing “baseline” values against detected values. Intermittent spikes andprogressions can be identified over a series of measurements. Anintermittent spike (either above or below average thresholds at certaintime instances) may indicate noise or may indicate a specific type offailure. Similarly, trends may indicate another failure or condition.

As such, the SNR and CFR data collection features and linecharacteristic prediction/detection mechanism of this embodiment ofsystem 100 provides a system that is able to monitor and regulate notonly electrical transmission but detection of problems within thetransmission line. Such detection allows a power supplier to determinebeforehand possible failures of a transmission line and to fix anyproblems in such line to avoid wide scale power outages.

In this disclosure, where a threshold or measured value is provided asan approximate value (for example, when the threshold is qualified withthe word “about”), a range of values will be understood to be valid forthat value. For example, for a threshold stated as an approximate value,a range of about 25% larger and 25% smaller than the stated value may beused. Thresholds, values, measurements and dimensions of features areillustrative of embodiments and are not limiting unless noted. Further,as an example, a “sufficient” match with a given threshold may be avalue that is within the provided threshold, having regard to theapproximate value applicable to the threshold and the understood rangeof values (over and under) that may be applied for that threshold.

It will be appreciated that the embodiments relating to circuits,algorithms, devices, modules, networks and systems may be implemented ina combination of electronic circuits, hardware, firmware and software.Firmware, software, applications and modules may be provided inexecutable software code that is stored in a physical storage device andexecuted on a processor of a device. The circuits may be implemented inwhole or in part through a combination of analog and/or digitalcomponents. In a circuit, an element may be connected to another elementeither directly or through another circuit. When a first element isidentified as being connected to another element, that first elementitself may be considered to be a “circuit”. The firmware and softwaremay be implemented as a series of processes, applications and/or modulesthat provide the functionalities described herein. The algorithms andprocesses described herein may be executed in different order(s).Interrupt routines may be used. Data may be stored in volatile andnon-volatile devices described herein and may be updated by thehardware, firmware and/or software.

It will further be appreciated that all processes, algorithms, stepsetc. as described herein may be conducted in a single entity. Forexample the calculations for the first and/or second stages may beprovided in the device itself. Such calculations may be conducted by oneor more modules in the device. The disclosure as such provides a methodof operating a device and/or a method for a function operating on thedevice. Alternatively, such calculations may be conducted in an off-sitelocation (e.g. a design laboratory) and the resulting circuits andcalculations can be provided to the device.

The present disclosure is defined by the claims appended hereto, withthe foregoing description being merely illustrative of embodiments ofthe disclosure. Those of ordinary skill may envisage certainmodifications to the foregoing embodiments which, although notexplicitly discussed herein, do not depart from the scope of thedisclosure, as defined by the appended claims.

1. A meter for monitoring usage of power provided by a powertransmission system to a site, the meter comprising: a communicationmodule to generate communications carried over the power transmissionsystem; a relay having a first position where power from the powertransmission system is connected to the site and a second position wherethe power is disconnected from the site; a request manager module toprocess messages received through the communication module from a headend associated with the power transmission system; a meter moduleconnected to a power feed associated with the power transmission systemto provide readings relating to the power used at the site; an eventmanager module to evaluate new events queued in a message queue receivedby the meter; and after evaluating the new events to generate and send amessage to the head end relating to the earliest event in the messagequeue; and a connection manager module to evaluate the readings and datarelating to past power usage at the site and generate connection signalsfor the relay for the meter to the power transmission system; toevaluate the readings and control the schedule manager in generating thecontrol signal; and to generate a signal for the relay to disconnect thepower when a condition in the power transmission system has beendetected by or reported to the meter.
 2. The meter for monitoring usageof power as claimed in claim 1, wherein the event manager modulefurther: sends a second message relating to the earliest event to thehead end when a response message is not received from the head end tothe message within a timeout period; and sends a third message relatingto a next earliest event in the message queue to the head end when theresponse message is received from the head end.
 3. The meter formonitoring usage of power as claimed in claim 1, further comprising: aschedule manager module to generate a control signal to provide afraction of the power to the site.
 4. The meter for monitoring usage ofpower as claimed in claim 3, wherein: the condition is an over-voltagecondition over a threshold over a period of time.
 5. The meter formonitoring usage of power as claimed in claim 4, wherein: the thresholdof voltage value is provided to the meter from a message receivedthrough the power transmission system.
 6. The meter for monitoring usageof power as claimed in claim 1, wherein: the connection manager modulegenerates a second signal for the relay to connect the power to the sitewhen a reset condition has been detected by the meter module.
 7. Themeter for monitoring usage of power as claimed in claim 1, wherein: theconnection manager module also generates a second signal for the relayto connect the power to the site when a disconnect condition has beendetected by the meter module.
 8. The meter for monitoring usage of poweras claimed in claim 1, wherein: the request manager module processes abroadcast message received from the head end of the power transmissionsystem relating to a cluster command for meters in a subnet that includethe meter.
 9. The meter for monitoring usage of power as claimed inclaim 1, wherein: the condition is detection at least one of opening acase of the meter and disconnection of the meter from the power.
 10. Themeter for monitoring usage of power as claimed in claim 1, wherein theconnection manager module further: generates the signal for the relayafter receiving a disconnect signal from the head end of the powertransmission system.
 11. The meter for monitoring usage of power asclaimed in claim 1, wherein the schedule manager module further: obtainsa plurality of readings from the meter module and provides results ofthe plurality of readings to the connection manager module.
 12. Themeter for monitoring usage of power as claimed in claim 11, wherein: theplurality of readings is made according to a schedule provided by theschedule manager module.
 13. The meter for monitoring usage of power asclaimed in claim 11, wherein the schedule manager module: updates ausage rate for readings made by the meter module.
 14. The meter formonitoring usage of power as claimed in claim 11, wherein the schedulemanager module: synchronizes a clock of the meter with a system timemanaged at the head end of the power transmission system.
 15. A methodfor monitoring usage of power provided by a power transmission system toa site through a meter, the method comprising: obtaining and storingreadings for a power feed associated with the site; evaluating thereadings and data relating to past power usage at the site; generatingconnection signals for the meter to the power transmission system inview of the readings; evaluating new events queued in a message queuereceived by the meter; after evaluating the new events, generating andsending a message to the head end relating to the earliest event in themessage queue; and controlling a relay having a first position where thepower is connected to the site and a second position where the power isdisconnected from the site when an over-voltage condition on the powertransmission system has been detected by or reported to the meter. 16.The method for monitoring usage of power provided by a powertransmission system to a site through a meter as claimed in claim 15,further comprising: sending a second message relating to the earliestevent to the head end when a response message is not received from thehead end to the message within a timeout period; and sending a thirdmessage relating to a next earliest event in the message queue to thehead end when the response message is received from the head end. 17.The method for monitoring usage of power provided by a powertransmission system to a site through a meter as claimed in claim 15,further comprising: evaluating the readings and controlling a schedulemanager to generate a control signal to provide a fraction of the powerto the site.
 18. The method for monitoring usage of power provided by apower transmission system to a site through a meter as claimed in claim15, further comprising: generating a connection signal to connect thepower to the site when a reset condition has been detected.
 19. Themethod for monitoring usage of power provided by a power transmissionsystem to a site through a meter as claimed in claim 15, wherein: therelay is also set to the second position when at least one of opening acase of the meter and disconnection of the meter from the power isdetected.